andythenorth

Extending NewGRF APIs - impedance mismatch

Term borrowed from https://en.wikipedia.org/wiki/Object%E2%80%93relational_impedance_mismatch

In no particular order

* not many OpenTTD devs familiar with grf spec
    * so designing and reviewing can be hard
* some of the requests from grf authors are misguided
    * interacting with newgrf authors can involve blah blah politics

andythenorth

switch (FEAT_TRAINS, SELF, intermodal_car_switch_colour_mapping_not_a_cargo_sprinter, vehicle_is_flipped) {
    1: return base_sprite_2cc + 16 * company_colour1 + company_colour2; 
    return base_sprite_2cc + 16 * company_colour2 + company_colour1; 
}
switch (FEAT_TRAINS, SELF, intermodal_car_switch_colour_mapping_cargo_sprinter, 0) {
    return base_sprite_2cc + 16 * company_colour2 + company_colour1; 
}
switch (FEAT_TRAINS, PARENT, intermodal_car_switch_colour_mapping_force_if_cargo_sprinter, vehicle_type_id) {
    3000: return intermodal_car_switch_colour_mapping_cargo_sprinter;
    return intermodal_car_switch_colour_mapping_not_a_cargo_sprinter;

andythenorth

switch (FEAT_TRAINS, SELF, intermodal_car_switch_colour_mapping_not_a_cargo_sprinter, vehicle_is_flipped) {
    1: return base_sprite_2cc + 16 * company_colour1 + company_colour2; 
    return base_sprite_2cc + 16 * company_colour2 + company_colour1; 
}
switch (FEAT_TRAINS, PARENT, intermodal_car_switch_colour_mapping_force_if_cargo_sprinter, vehicle_type_id) {
    3000: base_sprite_2cc + 16 * company_colour2 + company_colour1; 
    return intermodal_car_switch_colour_mapping_not_a_cargo_sprinter;
} 

andythenorth

Newgrf vehicles TL;DR

Each vehicle is an instance of a model type.
Each model type is an instance of one of the base game vehicles (engine, wagon, dual-head engine).

Vehicle instances have properties, which have gameplay effects.
Properties are generally initialised when a vehicle is built.
Many properties are mutable.
Properties are mutable via callbacks which are triggered on specific game events.
Vehicles can use logic in callbacks.

andythenorth

                    spriteset(ss_spritelayer_cargos_intermodal_cars_default_16px_box_DFLT_0_unflipped, "generated/graphics/intermodal_default_box_DFLT_16px.png") {
                        spriteset_template_asymmetric_unreversed_4_8_unflipped(10 + 0, NOANIM)
                    }
                    spriteset(ss_spritelayer_cargos_intermodal_cars_default_16px_box_DFLT_0_flipped, "generated/graphics/intermodal_default_box_DFLT_16px.png") {
                        spriteset_template_asymmetric_reversed_4_8_flipped(10 + 0, NOANIM)
                    }
                    switch (FEAT_TRAINS, SELF, switch_spritelayer_cargos_intermodal_cars_default_16px_box_DFLT_0, vehicle_is_flipped) {
                        1: return ss_spritelayer_cargos_intermodal_cars_default_16px_box_DFLT_0_flipped;
                        return ss_spritelayer_cargos_intermodal_cars_default_16px_box_DFLT_0_unflipped;
                    }

andythenorth

// Automatically generated by GRFCODEC. Do not modify!
// (Info version 32)
// Escapes: 2+ 2- 2< 2> 2u< 2u> 2/ 2% 2u/ 2u% 2* 2& 2| 2^ 2sto = 2s 2rst = 2r 2psto 2ror = 2rot 2cmp 2ucmp 2<< 2u>> 2>>
// Escapes: 71 70 7= 7! 7< 7> 7G 7g 7gG 7GG 7gg 7c 7C
// Escapes: D= = DR D+ = DF D- = DC Du* = DM D* = DnF Du<< = DnC D<< = DO D& D| Du/ D/ Du% D%
// Format: spritenum imagefile depth xpos ypos xsize ysize xrel yrel zoom flags

0 * 4 \d171529

1 * 6462 14 "C" "INFO"

andythenorth

            spriteset(ss_spritelayer_cargos_intermodal_cars_default_16px_box_DFLT_0_unflipped, "generated/graphics/intermodal_default_box_DFLT_16px_.png") {
                spriteset_template_asymmetric_unreversed_4_8_unflipped(10 + 0, NOANIM)
            }
            spriteset(ss_spritelayer_cargos_intermodal_cars_default_16px_box_DFLT_0_flipped, "generated/graphics/intermodal_default_box_DFLT_16px_.png") {
                spriteset_template_asymmetric_reversed_4_8_flipped(10 + 0, NOANIM)
            }
            switch (FEAT_TRAINS, SELF, switch_spritelayer_cargos_intermodal_cars_default_16px_box_DFLT_0, vehicle_is_flipped) {
                1: return ss_spritelayer_cargos_intermodal_cars_default_16px_box_DFLT_0_flipped;
                return ss_spritelayer_cargos_intermodal_cars_default_16px_box_DFLT_0_unflipped;
            }

andythenorth

# autopep8

container_type_gestalt_mapping = {'box': [
    IntermodalBox16px,
    IntermodalBox24px,
    IntermodalBox32px
],
    'bulk': [
    IntermodalFlatCar16pxStandard,
    IntermodalFlatCar24pxStandard,

andythenorth

    1: return custom_wagon_recolour_sprites + 16 * 0 /* recolour set */ + company_colour1;
    2: return custom_wagon_recolour_sprites + 16 * 1 /* recolour set */ + company_colour2;

andythenorth

switch (FEAT_TRAINS, SELF, switch_alt_var_41_match_ids, STORE_TEMP(var[0x61, 0, 0x0000FFFF, 0xC6], 0)) {
    return switch_alt_var_41_match_ids_0;
}
    switch (FEAT_TRAINS, SELF, switch_alt_var_41_position_in_vehid_chain_multiple_ids_127, [STORE_TEMP(-127, 0x10F), switch_alt_var_41_match_ids()]) {
        return 126;
    }
    switch (FEAT_TRAINS, SELF, switch_alt_var_41_position_in_vehid_chain_multiple_ids_126, [STORE_TEMP(-126, 0x10F), switch_alt_var_41_match_ids()]) {
        1: switch_alt_var_41_position_in_vehid_chain_multiple_ids_127;
        return 125;
    }